37,112 research outputs found
A versatile method for simulating pp -> ppe+e- and dp -> pne+e-p_spec reactions
No full textWe have developed a versatile software package for the simulation of di-electron production in pp and dp collisions at moderate beam kinetic energies (1-2GeV). Particular attention has been paid to incorporate different descriptions of the Dalitz decay Δ rightarrow Ne + e - via a common interface. In addition, suitable parameterizations for the virtual bremsstrahlung process NN rightarrow NNe + e - based on one-boson exchange models have been implemented. Such simulation tools with high flexibility of the framework are important for the interpretation of the di-electron data taken with the HADES spectrometer and demonstrates the wide applicability within the field of nuclear and hadronic physics
Theoretical analysis, optimization, and experimental evaluation of dual function DP R-EDFA
No full textA simple rate-equation model of double pass (DP), remotely-pumped Erbium-doped fiber amplifier (R-EDFA) is developed based on the Giles-and-Desurvire (1991) model of a single pass (SP) EDFA. The mathematical equations to calculate stimulated absorption-and-emission rate between levels 1 and 2 of SP EDFA are modified by integrating the reflected backward-propagating signal of the DP R-EDFA. Besides the signal amplification, dispersion compensation by the chirped-fiber Brag-grating (CFBG) inside the DP R-EDFA is also taken into account. The reflection losses of a signal by the CFBG are included in the backward-propagating signal of the DP R-EDFA. Considering a high gain and low noise figure (NF) by very low remote pump power as a main design objective, the design process of an optimized DP R-EDFA for a long haul optical-fiber-communication system (OFCS) is demonstrated. Robustness and stability of the DP R-EDFA rate-equation model developed are shown by analzing the numerical results and output shapes using various design parameters of the DP R-EDFA. Finally the DP R-EDFA, rate-equation model developed is validated with the help of experimental results
La science des données: Théorie et applications avec R et Python
No full textCe manuel explore les fondements de la science des données, en mettant l’accent sur les langages R et Python. Il couvre des aspects tels que le traitement des données, la visualisation, l’apprentissage machine et l’intelligence artificielle explicable. Les auteurs abordent également les enjeux de sécurité et de vie privée dans ce domaine. En somme, ce livre offre une vue d’ensemble complète pour quiconque souhaite plonger dans l’univers de la science des données
Adjective Syntax and (the absence of) noun raising in the DP
No full textThe paper is structured as follows. Section 2.1 introduces the basic classes of adjectives that constitute the factual core of the paper. Section 2.2 summarizes in greater detail the X° and the XP movement approaches to word order variation within the DP. Section 3 briefly discusses problems for both approaches. Sections 4.1, 5.1, and 5.2 draw from Alexiadou (2001) and contain a discussion of Greek DS and its relevance for a re-analysis of the word order variation in the Romance DP. Section 4.2 introduces refinements to Alexiadou & Wilder (1998) and Alexiadou (2001). Section 5.3. discusses certain issues that arise from the analysis of postnominal adjectives in Romance as involving raising of XPs. Section 6 discusses phenomena found in other languages, which at first sight seem similar to DS. However, I show that double definiteness in e.g. Hebrew, Scandinavian or other Balkan languages constitutes a different type of phenomenon from Greek DS, thus making a distinction between determiners that introduce CPs (Greek) and those that are merely morphological/agreement markers (Hebrew, Scandinavian, Albanian)
Practical extensions to cycle time approximations.for the G/G/m-queue with applications
No full textApproximate closed form expressions for the mean cycle time in a G/G/m-queue often serve as practical and intuitive alternatives to more exact but less tractable analyses. However, the G/G/m-queue model may not fully address issues that arise in practical manufacturing systems. Such issues include tools with production parallelism, tools that are idle with work in process, travel to the queue, and the tendency of lots to defect from a failed server and return to the queue even after they have entered production. In this paper, we extend popular approximate mean cycle time formulae to address these practical manufacturing issues. Employing automated data extraction algorithms embedded in software, we test the approximations using parameters gleaned from production tool groups in IBM's 200 mm semiconductor wafer fabricator
The classification of dp-minimal integral domains
No full textWe classify dp-minimal integral domains, building off the existing
classification of dp-minimal fields and dp-minimal valuation rings. We show
that if R is a dp-minimal integral domain, then R is a field or a valuation
ring or arises from the following construction: there is a dp-minimal valuation
overring O extending R, a proper ideal I in O, and a finite subring S in O/I
such that R is the preimage of S in O.Comment: 31 page
Outcomes and risk score for Distal Pancreatectomy with Celiac Axis Resection (DP-CAR) : an international multicenter analysis
No full textAbstract: BackgroundDistal pancreatectomy with celiac axis resection (DP-CAR) is a treatment option for selected patients with pancreatic cancer involving the celiac axis. A recent multicenter European study reported a 90-day mortality rate of 16%, highlighting the importance of patient selection. The authors constructed a risk score to predict 90-day mortality and assessed oncologic outcomes.MethodsThis multicenter retrospective cohort study investigated patients undergoing DP-CAR at 20 European centers from 12 countries (model design 2000-2016) and three very-high-volume international centers in the United States and Japan (model validation 2004-2017). The area under receiver operator curve (AUC) and calibration plots were used for validation of the 90-day mortality risk model. Secondary outcomes included resection margin status, adjuvant therapy, and survival.ResultsFor 191 DP-CAR patients, the 90-day mortality rate was 5.5% (95 confidence interval [CI], 2.2-11%) at 5 high-volume (1 DP-CAR/year) and 18% (95 CI, 9-30%) at 18 low-volume DP-CAR centers (P=0.015). A risk score with age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) score, multivisceral resection, open versus minimally invasive surgery, and low- versus high-volume center performed well in both the design and validation cohorts (AUC, 0.79 vs 0.74; P=0.642). For 174 patients with pancreatic ductal adenocarcinoma, the R0 resection rate was 60%, neoadjuvant and adjuvant therapies were applied for respectively 69% and 67% of the patients, and the median overall survival period was 19months (95 CI, 15-25months).ConclusionsWhen performed for selected patients at high-volume centers, DP-CAR is associated with acceptable 90-day mortality and overall survival. The authors propose a 90-day mortality risk score to improve patient selection and outcomes, with DP-CAR volume as the dominant predictor
A common HLA-DPA1 variant is associated with hepatitis B virus infection but fails to distinguish active from inactive Caucasian carriers
No full textBackground and Aims: Chronic infection with the hepatitis B virus (HBV) is a major health issue worldwide. Recently, single nucleotide polymorphisms (SNPs) within the human leukocyte antigen (HLA)-DP locus were identified to be associated with HBV infection in Asian populations. Most significant associations were observed for the A alleles of HLA-DPA1 rs3077 and HLA-DPB1 rs9277535, which conferred a decreased risk for HBV infection. We assessed the implications of these variants for HBV infection in Caucasians.
Methods: Two HLA-DP gene variants (rs3077 and rs9277535) were analyzed for associations with persistent HBV infection and with different clinical outcomes, i.e., inactive HBsAg carrier status versus progressive chronic HBV (CHB) infection in Caucasian patients (n = 201) and HBsAg negative controls (n = 235).
Results: The HLA-DPA1 rs3077 C allele was significantly associated with HBV infection (odds ratio, OR = 5.1, 95% confidence interval, CI: 1.9–13.7; p = 0.00093). However, no significant association was seen for rs3077 with progressive CHB infection versus inactive HBsAg carrier status (OR = 2.7, 95% CI: 0.6–11.1; p = 0.31). In contrast, HLA-DPB1 rs9277535 was not associated with HBV infection in Caucasians (OR = 0.8, 95% CI: 0.4–1.9; p = 1).
Conclusions: A highly significant association of HLA-DPA1 rs3077 with HBV infection was observed in Caucasians. However, as a differentiation between different clinical courses of HBV infection was not possible, knowledge of the HLA-DPA1 genotype cannot be translated into personalized anti-HBV therapy approaches
Investigation of Unexpected Dynamic Vessel Response of a SSCV during DP-Operations
No full textDuring offshore construction with a Semi-Submersible Crane Vessel (SSCV) the vessel is station keeping by means of Dynamic Positioning (DP). DP enables a vessel to keep position and heading by utilizing its own propulsion, while being exposed to the environmental forces caused by waves, wind and current. In a comparison study between offshore measurements and time-domain simulations, an increased vessel/thruster response for the offshore measurement was observed. The results revealed, that in operational environmental conditions, the measured vessel response shows increased oscillations in Surge, Sway & Yaw, with periods of approx. 3-5 min. The goal of this thesis was to determine the causes for such an increased dynamic vessel response, which are not captured in time-domain simulations. At present, numerical methods and time-domain simulations that assess the DP performance of a vessel (e.g. aNySIM) assume a quasi-static current of which the variation is only caused by the tides. One thesis is, that time-varying currents on a scale of 1 to 5 minutes can cause an increased vessel response. Furthermore, the DP System as it is used onboard is not captured in aNySIM simulations. This means that the characteristics of the DP System onboard are but not represented in full detail in time-domain simulations. Vortex Induced Motion (VIM) has previously been observed to affect multi column floaters. However, the influence on a SSCV during DP-operations has not yet been studied. In this thesis it was investigated whether the unexpected increased motions originate from time-varying currents, VIM or the DP System itself. A significant challenge was posed to find current measurement data with a small enough time step to confirm the presence of such time-varying currents. One 45 min current measurement with a sampling rate of 1Hz became available. This measurement shows that time-varying currents on a scale of 1 to 5 minutes exist and cannot be assumed to be quasi-static. More research is required to confirm their presence. However, with this limited available data it was shown that time-varying currents can cause an unexpected motion response of a SSCV during DP-operations.In order to obtain the DP System characteristics, a DP Response Amplitude Operator (RAO) assessment was conducted wherein the spring and damping terms were derived as demanded by the controller and as experienced by the vessel. This assessment showed that between 20% to 67% of the demanded critical damping is lost over the control loop of the DP System. These damping losses cause the vessel to overshoot and the damped natural period to decrease. To determine the effects of VIM, current load tests carried out on the hull of an SSCV have been investigated. It was determined that strong currents on column type floaters can cause fluctuating forces and moments that originate from vortex shedding. Further, with real-time simulations it was demonstrated, that also VIM causes an increased, previously unknown, motion response of a SSCV. Lastly, a method was developed to extrapolate the current load test results to velocities below 2kn. Subsequently, in time-domain simulations it was shown that for current velocities above 0.5kn, the vessel experienced forces and moments that caused it to fluctuate around its setpoint
HLA-DP allele-specific T cell responses to beryllium account for DP-associated susceptibility to chronic beryllium disease
No full textOccupational exposure to small molecules, such as metals, is frequently associated with hypersensitivity reactions, Chronic beryllium (Be) disease (CBD) is a multisystem granulomatous disease that primarily affects the lung, and occurs in similar to3% of individuals exposed to this element. Immunogenetic studies have demonstrated a strong association between CBD and possession of alleles of HLA-DP containing glutamic acid (Glu) at position 69 in the HLA-DP beta -chain. T cell clones were raised from three patients with CBD in whom exposure occurred 10 and 30 years previously. Of 25 Be-specific clones that were obtained, all were restricted by HLA-DP alleles with Glu at DP beta 69, Furthermore, the proliferative responses of the clones were absolutely dependent upon DP beta Glu(69) in that a single amino acid substitution at this position abolished the response. As befits a disease whose pathogenesis involves a delayed type hypersensitivity response, the large majority of Be-specific clones secreted IFN-gamma (Th1) and little or no IL-4 (Th2) cytokines, This study provides insights into the molecular basis of DP2-associated susceptibility to CBD
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